Adding a "fade out" to multiple comps

I have around 25 lower thirds that i created, now the client wants to change their duration.
I know I can set the work area for all of them in Media encoder- the problem is they need to fade out with an opacity key or any other effect (whatever works).

Does anyone know of a way to apply this effect on multiple comps instead of doing it one by one?
i have searched for a script or something else but found nothing.

p.s
I dont know if it matters but i export them with alpha (bg needs to be transparent)